Electrical enclosures include in the walls knock-outs which have a center and may include one or more concentric rings which must be removed for the passage of wiring or conduit. The usual practice is to remove the selected knock-out before the enclosure is installed and before wiring or fixtures are installed. This isn't always possible.
To remove the knock-out, it is usually struck with an implement such as a screwdriver, in turn struck by a hammer. When the knock-out is deflected it is then grasped by needle nose pliers and twisted out. If the box is already installed the process can result in damage or distortion to the enclosure or the bracketry on which it is mounted. In other words the box may be knocked loose or out of line. If the box already contains wiring or a wired fixture there is also a clearance problem and the process may result in damage to the wiring or fixture in place. If proper precautions aren't taken the hot wires also present a further safety problem. Skinned knuckles are not uncommon in the above described process as well as the noted damage to the box, fixture, wiring or mounting bracketry. The process is also time consuming.
Accordingly, there is a need for a convenient tool which will enable the knock-outs more readily to be removed.
A prior art search has revealed special knock-out tools in U.S. Pat. Nos. 3,713,200 and 4,167,058, both of which require to be struck or hammered to obtain the force to deflect the knock-out. The search also revealed a variety of plier type tools such as U.S. Pat. Nos. 4,787,139; 4,881,434; 4,170,125; 2,154,580; 4,075,749; and 4,149,435, for a variety of purposes, the latter U.S. Pat. No. 4,149,435 being for the purpose of removing identification slugs from the heads of keys.